For many years the harvesting of raisins has largely been a manual operation. Raisins are simply grapes which are left on a vine which as been severed from the main stalk, so that the grapes dry into raisins. Then the bunches of dried grapes (which are now raisins) are manually gathered and the raisins removed from the stems and branches. Automated picking machines have not, to the best knowledge of the applicants, been particularly successful.
One common method of providing and harvesting raisins is for the workers to move down the row of upright grape plants, snipping off the bunches of grapes and permitting them to fall on paper sheets which rest on the ground. After several weeks of the grapes drying in the sun, these are then manually gathered so that the dried grapes (i.e. raisins) can be removed.
In recent years, there have been various attempts to improve the methods of growing grapes to increase the yield. One such attempt is to initially grow the grape plant upwardly so that it is vertically aligned, this commonly being accomplished by guiding the plant between laterally spaced wires that extend horizontally along posts that are arranged in rows. The uppermost vertically aligned shoot of the grape plant is called the primocane. In the first year of growth, this primocane does not grow grapes, but does so in the second year when it becomes a fruiting cane. One more recent attempt to improve the yield of the grapes is that early in the second year, the primocane shoots that have grown the prior year are moved out of vertical alignment and manually positioned so that they extend upwardly and laterally at about a 45.degree. angle. This can simply be accomplished by providing a plurality of support arms that extend from the main posts at an upward and lateral slant (e.g. at 45.degree.), and the primocane shoots are positioned on the wires which extend horizontally along these slanted arms. During the second year, the primocane shoots now become fruiting cane and bear the bunches of grapes.
When it is desired to harvest these grapes as raisins, the base of the fruiting cane branches are totally severed from the stalk, and these branches, with the grapes still hanging in bunches therefrom, are simply permitted to stay resting on the wires between the slanted arms. After several weeks, the grapes have dried sufficiently so that they now have become raisins ready for harvest.
While for many years there have been various types of harvesting machines to harvest a variety of fruit, such machines have not (to the best knowledge of the applicants herein) become adopted to any great extent for commercially harvesting grapes which are intended to be sold as fruit. One of the reasons for this is that it is rather difficult to remove the grapes from the stems. While some berries will drop from the stem or vines when the vine or stem is shakened, this has proven to be much more difficult with grapes, and also with raisins. For example, an accelerating force of only a few "G's" will shake many berries loose from the stems or vines. On the other hand, for grapes and raisins it may take a force substantially greater to shake the grapes or raisins loose.
Accordingly, when grapes are harvested in a manner so that there is little if any damage, this is generally a manual operation. When grapes are harvested by machines, they are generally smashed and damaged to a substantial extent, and these are grapes which are used for other purposes (e.g. wine), but not for grapes to be sold in the undamaged form.
It is with the foregoing in mind that the present invention has been developed.